Higher-Order Structures of Proteins in Solution Explored by Using Low-Frequency Raman Optical Activity

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K05524
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 34020:Analytical chemistry-related
• Research Institution: Osaka University
• Principal Investigator: Yamamoto Shigeki 大阪大学, 理学研究科, 助教 (60552784)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: キラリティ / タンパク質構造

Outline of Final Research Achievements

To analyze chiral higher-order structures of proteins, their fluctuation in solutions, and chiral solute-solvent interactions, we have extended a measurable region of chiral vibrational spectroscopy, Raman Optical Activity (ROA), to the lower frequency region and measured low-frequency ROA of proteins in solutions at the first time. A new spectrometer was developed for the measurements and peak assignments were attempted by comparing spectra of proteins of which crystal structures are well-known. Furthermore, experimental spectrum of an alpha-helical polypeptide was well reproduced by quantum mechanical simulation, which explored that the low-frequency ROA can reflect a long-range interaction of alpha-helix within about two helix turns and its structural fluctuation in solutions.

Free Research Field

分光分析

Academic Significance and Societal Importance of the Research Achievements

ラマン光学活性の測定範囲を低波数領域にまで拡張し，溶液中タンパク質の測定を初めて行ったことは，タンパク質のキラル高次構造とその揺らぎを直接に簡便に測定する新規な方法を開拓した点で学術的意義が高い。生物のキラル選択的な反応の一因はタンパク質のキラル高次構造とその反応にあると考えられるため，その解析手法の開発はキラル薬剤の開発の一助となるだろう。